Spaceflight Insider

India’s PSLV rocket to launch six Singapore satellites

Tomasz Nowakowski

December 15th, 2015

A PSLV rocket lifts off from the launch site at Satish Dhawan. Photo Credit: ISRO

India’s workhorse Polar Satellite Launch Vehicle (PSLV) is ready to launch six satellites under the TeLEOS-1 mission for Singapore on its 32nd flight. The mission, designated PSLV-C29, will see the rocket blasting off at 7:30 a.m. EST (12:30 GMT) on Wednesday, Dec. 16, from the First Launch Pad at the Satish Dhawan Space Centre (SDSC) in Sriharikota.

The flight will be conducted by the Indian Space Research Organisation (ISRO). The Mission Readiness Review (MRR) committee and Launch Authorisation Board (LAB) have already given the green light for the launch and the 59-hour countdown started as planned on Monday. Propellant filling operations began just a few hours after the countdown had commenced.

PSLV-C29 on the First Launch Pad with Vehicle Assembly Building in the background. Photo Credit: ISRO

The rocket will use a “typical” PSLV flight profile to fulfill its mission of deploying six satellites. The vehicle will fly in its ‘core-alone’ configuration – without the use of solid strap-on motors (this marks the 11th time this version of the PSLV has been used).

The rocket’s first stage will separate about one minute and 53 seconds after liftoff. One minute later, the heat shield will be detached from the launch vehicle and the second stage will continue its flight until separation at four minutes and 20 seconds after the rocket has left the pad.

The third stage should fly for five minutes and 23 seconds, separating at T+9 minutes and 44 seconds. The fleet of satellites are expected to be deployed 18-21 minutes into the flight. The mission will end in a restart and cutoff of the fourth stage, at approximately 67 and a half minutes after launch.

The satellites should then be injected into a circular low-Earth orbit (LEO) at an altitude of 341 miles (550 km), inclined some 15 degrees to the equator.

The main passenger of the PSLV-C29 mission is the TeLEOS-1 satellite. Other payloads include smaller spacecraft – two micro-satellites (VELOX-CI, Kent Ridge-1) and three nanosatellites (VELOX-II, Athenoxat-1, Galassia).

TeLEOS-1, built by ST Electronics, is Singapore’s first commercial Earth observation satellite. Weighing 882 lbs. (400 kg), it has dimensions 6.23 by 6.56 by 5.25 feet (1.9 by 2 by 1.6 m). It features an electro-optical camera and four deployable fixed solar arrays. The satellite will be operated by AgileSpace company. It is expected to be operational for five years.

TeLEOS-1 will deliver high-resolution imagery – 3.28 feet (1 m) panchromatic – for precise and high temporal change detection, mapping, and in-depth image analysis. The images will be collected with an average revisit time of 12 to 16 hours.

“It will enable decision makers and users convenient access to high temporal imagery and geospatial solutions to respond to time-sensitive events, such as homeland security and border control, maritime situation awareness, and disaster monitoring and management around the equatorial belt,” AgileSpace states.

VELOX-CI, built by Nanyang Technological University (NTU) in Singapore, is a 271 lbs. (123 kg) experimental microsatellite mission to study tropical climates. It will be operated by NTU, using a special technique known as radio occultation and advanced algorithms, to obtain weather data such as the upper atmospheric temperature, humidity, and pressure, which are useful for long-term climate studies.

VELOX-CI features two deployable solar arrays and its payload consists of a GPS occultation experiment, experimental RF probe, and other experimental missions such as altitude determination with GPS.

The VELOX-II is a 28.6 lbs. (13 kg) six-unit CubeSat. It is a part of NTU’s Undergraduate Satellite Program, which provides an opportunity for engineering students to participate in a multidisciplinary hands-on space project. It features two deployable fixed solar arrays and will be carrying experimental satellite-based communication hardware.

TeLEOS-1 and nanosats on the payload adapter. Photo Credit: ISRO

Kent Ridge-1 is a hyperspectral imaging microsatellite developed by the National University of Singapore (NUS) together with Berlin Space Technologies (BST), designed for Earth observation purposes. It weighs 172 lbs. (78 kg) and is based on BST’s LEOS-50 platform. It will be operated by NUS for five years.

The Kent Ridge-1 spacecraft carries three payloads: two medium resolution hyperspectral imaging payloads based on the Fourier transform recovery (FTR) method (PPL1 and PPL2) developed by NUS, and one high-resolution video payload (SPL) developed at BST. These instruments will enable multitudes of new applications in the monitoring of land, water, and vegetation and will be useful to contribute towards the effort to prevent and manage such disasters in this region.

Athenoxat-1 is a three-unit Earth-observing CubeSat developed by Microspace Rapid Pte Ltd. of Singapore to demonstrate the functionality of a night vision optical payload on a CubeSat-Class Nanosatellite. It features four deployable fixed solar arrays and solar cells.

The Galassia two-unit CubeSat, developed by NUS, is designed for atmospheric research. It carries two payloads: one measures the total electron count in the Ionosphere, and the other, named Small Photon-Entangling Quantum System (SPEQS), will generate and detect photon pairs. The satellite weighs 7.5 lbs. (3.4 kg) and features solar cells.

The four-stage PSLV booster is India’s most reliable launch vehicle. It has been in service for more than twenty years and has been used to launch various satellites for some of the country’s most historic missions, such as the Chandrayaan-1, Mars Orbiter Mission (MOM), Space Capsule Recovery Experiment, and Indian Regional Navigation Satellite System (IRNSS). The rocket has delivered more than 40 satellites to space for 19 countries. PSLV is capable of lofting up to 3.25 metric tons to LEO and about 1.42 metric tons to geosynchronous transfer orbit (GTO).

The rocket uses an Earth-storable liquid rocket engine for its second stage, known as the Vikas engine, developed by the Liquid Propulsion Systems Centre. The third stage of the PSLV is a solid rocket motor that provides the upper stage’s high thrust after the atmospheric phase of the mission. The fourth stage is composed of two Earth-storable liquid fueled engines.

The 144 ft. (44 meters) tall CA version of the PSLV, which will be used in Wednesday’s launch, is the upgraded version of the rocket in its standard configuration. The vehicle, with a mass of 230 metric tons at liftoff, does not include the six strap-on boosters used by the PSLV standard variant.

Wednesday’s mission will be India’s fifth orbital liftoff this year. The country’s next launch is scheduled for January 2016 when a PSLV-XL rocket will send the IRNSS-1E navigation satellite into space.

Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.